1. Field of the Invention
The present invention relates to a method for manufacturing a substrate provided with a semiconductor layer with an insulating layer therebetween, and particularly relates to a method for manufacturing an SOI (silicon on insulator) substrate. In addition, the present invention relates to a method for manufacturing a semiconductor device using a substrate over which a semiconductor layer is provided with an insulating layer interposed therebetween.
2. Description of the Related Art
In recent years, integrated circuits using an SOI substrate where a thin single crystal semiconductor layer is formed on an insulating surface, instead of a bulk silicon wafer, have been developed. The use of an SOI substrate can reduce parasitic capacitance between a drain of a transistor and a substrate; thus, SOI substrates have attracted attention for their ability to improve performance of semiconductor integrated circuits.
Smart Cut (registered trademark) method is known as one of methods for manufacturing an SOI substrate (for example, see Patent Document 1). An outline of a method for manufacturing an SOI substrate by Smart Cut method is described below. First, hydrogen ions are implanted into a silicon wafer by an ion implantation method to form a microbubble layer at a predetermined depth from the surface. Next, the silicon wafer into which hydrogen ions have been implanted is bonded to another silicon wafer with a silicon oxide film interposed therebetween. Then, by heat treatment, the microbubble layer serves as a cleavage plane and part of the silicon wafer into which hydrogen ions have been implanted is separated in a thin film shape along the microbubble layer. Accordingly, a single crystal silicon film can be formed over the other bonded silicon wafer. Smart Cut method may also be referred to as a hydrogen ion implantation separation method.
In addition, a method has also been proposed in which a single crystal silicon layer is formed over a base substrate formed using glass by such Smart Cut method. Since glass substrates can have a larger area and are less expensive than silicon wafers, the glass substrates are mainly used in manufacturing liquid crystal display devices and the like. A large-sized inexpensive SOI substrate can be manufactured using such a glass substrate as a base substrate.
[Reference]
[Patent Document 1] Japanese Published Patent Application No. H05-211128